Genome sequencing gets cheaper by the day

Having our own DNA blueprints will revolutionise medical diagnosis and treatment. Photo / Glenn Jeffrey

A scientist has deciphered his entire genetic code for the price of a sports car in a development that could soon lead to even cheaper genome sequences, which will revolutionise medical treatment.

The cost of sequencing the three billion letters of the human genome was, only a few years ago, priced in the region of many tens of millions of pounds, but Professor Stephen Quake of Stanford University in Palo Alto, California, has now done it for less than £31,000 ($73,000).

Using a revolutionary technique he helped pioneer six years ago, Professor Quake has produced a "working draft" of his own genome that medical scientists can now analyse for genetic predispositions to physical and mental disorders and traits, as well as possible adverse reactions to certain drugs.

Fewer than a dozen people have had their entire genome sequenced, but all of these DNA blueprints have cost many hundreds of thousands of dollars and many hundreds of hours of expert labour and costly laboratory time, putting the practice well out of reach of ordinary citizens and the National Health Service.

But Professor Quake said there was nothing to stop advances in genetics refining the technique still further to make it cheap enough for ordinary people to use as an aid to medical diagnosis and treatment.

Proponents of such genetic screening believe it will lead to the development of "personalised medicine", when treatment is decided on the basis of a person's individual genetic make-up, rather than a "one size fits all" approach.

When the Human Genome Project - the international effort to decipher the entire DNA of all human chromosomes - was established in 1990, the cost of working out the full genetic blueprint of a typical genome was estimated to be about £1.8 billion.

By the time the first draft of a composite genome made from many different people was published in 2001, the cost had fallen dramatically.

Last year, James Watson, who in 1953 discovered the double helix structure of DNA with Cambridge colleague Francis Crick, had his own genome sequenced for less than £600,000, but it still entailed an army of technicians and a huge investment in expensive laboratory equipment.

Professor Quake said he managed to sequence his own genome in two months with the help of just two colleagues.

"This is the first demonstration that you don't need a genome centre to sequence a human genome. It's really democratising the fruits of the genome revolution and saying that anybody can play this game," he said.

"This can now be done in one lab, with one machine, at a modest cost. It's going to unleash an enormous amount of creativity and really broaden the field. Some doctors are starting to poke and prod me to see how they can couple my genome with medicine."

One of the earliest findings from his own genome sequence is that Professor Quake has inherited a rare mutation associated with an increased risk of developing heart disease, which could explain observations he and other members of his family have made about the health of earlier generations.

"If you know your uncle had something, you kind of discount that you can get it, but to see you've inherited the mutation for that is another matter altogether," he said.

Genome sequencing usually involves making many copies of a person's DNA before the detailed breakdown of each letter of the four-letter code can be done.

But Professor Quake's invention - published in the journal Nature Biotechnology - can carry out the sequencing on a single DNA molecule from an individual, making it simpler and cheaper than the standard method. One of the reasons why the method is so cheap is that it could use the information gleaned by the Human Genome Project on what a typical genome looks like.

This enabled scientists to compare the individual sequences from Professor Quake's fragmented pieces of DNA to build up a picture of his overall genetic code.

But Professor Quake warned that the advent of cheap genome sequences - a central feature of the cult 1997 film Gattaca, set in a fictional future when everyone is judged on their genetic make-up - could lead to a new set of ethical problems that have yet to be addressed by society.

"The US$1000 genome is just around the corner, and when everybody will be able to have their genome sequenced, what's it going to mean for privacy, health insurance and decisions about human health? The technology is not going to let people escape these ethics and policy questions," Professor Quake said.

"Are we going to require people, based on their genetic inheritance, to modify their behaviour, or just suggest it? Your insurance company could ask you to have a certain diet or they're not going to cover you. Is that what we want?"

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